Cessna 152 landing technique
#11
Maintain upwind until -300 ft from pattern altitude, 2100 RPM in the pattern, about 90 knots. Abeam, pull back power to slow to 85, carb, flaps 10. Base, slow to 70-75, flaps 20. Final, Pitch up for 60, once 60 is reached, and runway can be made with out power, throttle idle. Acrft glided in all the way without power.
I'm sure your instructor has introduced "Pitch + Power = Performance" meaning that for any pitch, power, and configuration combination you can expect a predicable flight path whether it's a climb, decent, or level.
Pattern work puts that to the test and it sounds like you're doing it just fine. As you pull off power and maintain a level attitude (and add flaps) the airspeed decays until you reach approach speed at which time you reduce the pitch to descend (around 1500rpm, horizon halfway through the windshield, and flaps extended if I recall). Again for any pitch and power setting you can expect a known performance.
Pulling the power off and "gliding in" should only be done once you have the runway made, but maybe it's helpful to think about the power reduction from approach rpm to idle as a smooth gradual maneuver to arrive at a landing pitch at idle power at touchdown (pitch + power = performance).
Your instruction sounds "normal" as you explain it, the only thing I question is your description of "glide it in", I trained my students to arrive at idle on short final with runway "made". As a rule, I find that "chop and drop" introduces larger pitch changes that can be more of a distraction for primary students. Also, the chop and drop technique in more complex aircraft can shock cool the motor and lead to failures.
That said, you will practice power off landings (simulated eng failures) and short and soft field landing that will be the exception to the above. As mentioned in this thread, the power reference I gave you is just an example, follow the instruction you're paying for in the specific aircraft that you're flying.
#12
I typically have my students establish a glide and configure the airplane on downwind abeam the touchdown point with 10 degrees flaps, then add flaps on base and final. Trim is very important. You did not mention if you are pre or post solo and it seems your instructor is looking for something specific with this technique. Ask him. As far as crab and slip go, upon initial turn to final, crab into the wind to hold the centerline. The transition to slip can occur as late as the flare/touchdown. For learning purposes, transitioning to the slip at least 1/2 mile final will help you figure out what is going on. Forget formulas. Use the rudder to keep parallel to the centerline and aileron to hold the centerline. Think of them as two separate things. As the airspeed decays more input will be needed to hold the centerline (aileron) and parallel it (rudder). Check out tha Airplane Flying Handbbok H8083-3
#13
Is this commonly accepted practice? Also, with respect to crosswind landings, I use the crab to slip method. When turning final, say I have a x wind from the right. Do i align the nose of the arcft with the centerline first, notice drift, then crab, or do I just "guess" and turn the plane to the right(crab) a little bit and see, then make adjustments?
On the 2nd point, I find that the pilot has to be a pretty advanced pilot to employ that technique, as the issue is usually "do you have enough control with the aileron deflection to stay on the runway?". If you slip after turning final, you'll have a good idea of whether you'll have enough aileron control and the ability to stay on the runway. You may be able to land on the center of the runway by crabbing it down the whole way and then putting in aileron as you land, but you may also get quickly swept off the runway. By putting this control input in earlier, you will get used to using it, and it will become second nature, so you'll keep it in all the way to touchdown and hopefully beyond. If the wind is so great that you can't keep it from drifting down final, think about what's going to happen when trying to keep enough input in as the effectiveness decays due to slowing down. I know plenty of pilots in light aircraft that have been swept right off the runway. I personally use this method in light aircraft and throw in that aileron while keeping the axis aligned so I have that good idea of whether I'll have the control later in the approach/landing. In different and bigger aircraft, I use different methods. Airliners employ the crab and kickout method because they have engines/wings that will scrape and they have spoilers that instantly weight the wheels and stop the airplane from flying. You probably don't have those features on your aircraft.
Last edited by JamesNoBrakes; 09-20-2014 at 08:06 PM.
#14
#16
I need a 2nd opionon on the strategy my cfi has taught me on how to land the 152.
My CFI tells me that once I turn final, I pitch for 60 knots, and once 60 knots is reached, to idle the power(assuming I can glide from cut off point to Rwy) and glide the airplane in. Is this commonly accepted practice? Also, with respect to crosswind landings, I use the crab to slip method. When turning final, say I have a x wind from the right. Do i align the nose of the arcft with the centerline first, notice drift, then crab, or do I just "guess" and turn the plane to the right(crab) a little bit and see, then make adjustments?
My CFI tells me that once I turn final, I pitch for 60 knots, and once 60 knots is reached, to idle the power(assuming I can glide from cut off point to Rwy) and glide the airplane in. Is this commonly accepted practice? Also, with respect to crosswind landings, I use the crab to slip method. When turning final, say I have a x wind from the right. Do i align the nose of the arcft with the centerline first, notice drift, then crab, or do I just "guess" and turn the plane to the right(crab) a little bit and see, then make adjustments?
Sounds ok. I do (and teach) 60 on final with full flaps, approx 1600rpm w/carb heat ON of course, to maintain the vasi/papi (heavy headwinds of course will need more power), smoothly go to idle with runway made and aim for the numbers/threshold at 60-55. 55 being short final. Helps with reducing float. Just not much slower and it could get hairy though. Stall speed with full flaps is less than 40, so thats not the issue initially. however the sink rate will be surprising, if you do go significantly less than 55. This causes an inexperienced pilot to want to "pull up, and save the sink" so to speak, which is what causes the stall in this situation. but the right way to manage an unintentional(or intentional) low speed/high sink rate is With power and pitch. GO AROUND!
As for crabbing, yes. Guess. Its an educated guess that comes with practice. Also, you will be able to make faster judgements/observations of drift, with practice. The book actually says that turning to final, then crabbing again (left traffic, right crosswind) is incorrect. (This is why we do rectangular courses BTW) Only turn as much as you think you need. For example, normal base to final is 90degrees. So assuming left traffic, and a right 5 knot direct crosswind. Id turn 85 degrees of the 90, and then see how it goes. Either turn more, or back to the right if so needed.
If you wan to get technical, use your E6b and just find out what a 60knot KIAS, 5-10-15 knot crosswind will need for crab. (Pre-flight of course, not while in the pattern) And just keep those as an approx angle. Interpret the knots inbetween
Last edited by Aviator89; 09-20-2014 at 08:24 PM.
#17
Question: How much power in reserve do you have for downdrafts if you're following the VASI with full flaps in heavy headwinds (in a slow aircraft where headwind is significant)?
#19
True. Looking outside, It's how we fly VFR. But imagine the OP's situation. Student pilot, having a hard time grasping crabbing on final and x-winds (by looking outside and choosing a crab angle). If you read the whole response, you would see that I did first say to make and educated guess and look outside. To initially make your educated guess a little more accurate(if you are really, really having a difficult time figuring it out) feel free to play around with an E6B and see what different crosswinds need in terms of crab. Just to get an idea for future situations, it's good to have a reference or some place to start WHILE LEARNING it for the first time. And the OP was having a hard time adjust from no-wind to cross wind.
Not to actually plan a crab angle for landing every-time you go fly, like you would do a XC flight plan haha.
Last edited by Aviator89; 09-21-2014 at 06:34 AM.
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